Only Valleywag could find a cloud in the silver lining of the latest survey of the business mood in Northern California in the second quarter. Substantial margins of local chief execs polled by Vistage, a group in which high-tech is most heavily represented, saw their sales and profitability on an upward trend. But company bosses are a little less bullish than they were three months ago. For instance, 52% saw profitability improving, compared with 20% who expected a decline: a margin of 32%. In the first quarter, that margin was 47%. In confidence surveys like this one, it's the trends that matter. And the trend in Bay Area business confidence is down.